Like waves on a clear blue sea, or twisting wind-swept clouds, these whimsical designs are an artistic expression of spirit and uniqueness. Sapphire is the birthstone of September, and one of the most popular gemstones on the jewelry scene today. The deep blue color of a sapphire ring is just right for an evening out. The birthstone of December, the intense deep blue color of a london blue topaz ring can evoke thoughts of warm Caribbean nights.